Illegal immigrant profiles hard to discern from legal residents

Most illegal immigrants in the United States are Hispanic, but a relatively small share of Hispanics are illegal immigrants.

Those two groups, however, are more closely tied in some key demographic areas, such as income and education levels, than either group is with the U.S. population as a whole.

The facts, drawn from Census Bureau records and estimates by the Pew Hispanic Center, form a demographic tightrope that police in Arizona must navigate when they begin enforcing the new immigration law on July 29.

Distinguishing between a documented and an undocumented Hispanic person could prove difficult without intensive probing, complicating efforts to both enforce the tougher law and avoid illegal racial profiling.

Inability to speak English, along with lack of an ID issued by a government agency, could indicate illegal status. But not always. The Census Bureau estimates that there are nearly 39,000 U.S.-born Arizona residents who speak Spanish but don't speak English well or at all.